Pulp molding machine



1933. M. P. CHAPLIN 1,920,292

PULP MOLDING MACHINE Filed March 29, 1928 INVENTOR Merle 6/72 01 2'72 m riifi Patented Aug. 1, 1933 PATENT OFFICE 1,920,292 PULP MOLDING MACHINE Merle P. Chaplin, Waterville, Maine, assignor, by mesne assignments, to Fidelity Trust Company,

Portland, Trustee Maine, 'a Corporation of Maine,

Application March 29, 1528. Serial No. 255,551 25 Claims. (01. era-57.)

This invention relates topulp molding machines.

. In pulp molding machines it is common practice to deposit a layer of pulp or like material on forming dies and to compress the pulp layer and remove a large proportion of the moisture therefrom by suction. The articles are then transferred or deposited on conveyors and are removed from the machine to suitable driers.

This invention has for its salient object to dry molded pulp articles during the passage of the articles through the molding machine.

Another object of the invention is to provide a die, such for instance as a transfer die, with heating and drying means.

Further objects of the invention will appear from the following specification taken in connection with the drawing in which there is shown a sectional elevation of a machine having dies constructed in accordance with the invention.

The invention briefly described consists of a die for pulp molding machines mounted on a rotatable carrier, the face or outer surface of the die being formed of metal having a relatively high electrical resistance and forming a part of an electric heating circuit.

Further details of the invention will appear from the following description.

In the form of the invention illustrated in the drawing there is shown a carrier mounted on a shaft 10 and comprising a hub 12 and radial spokes or arms 13 having secured to the outer ends thereof dies 14.

Each die comprises a back plate 15 formed on or secured to one of the arms 13, an outer face or surface 20 formed of metal having a relatively high electrical resistance and a liner 21 disposed within the outer face 20 and formed of suitable heat insulating material.

The members 20 and 21 are perforated, as shown at 25, and a suction conduit 26 is carried by the back plate 15 and communicates with the chamber 27 formed within the die between the liner 21 and the plate 15. It will be obvious that other means than suction could be used, if desired, to secure'the articles to the dies. The use of suction in such dies is, however, of very great advantage and a preferred basis of operation in that the suction carries away the vapors generated by the heat of the die so that the rate of drying is increased and internal bubbles or blisters in the article avoided. The time of drying is thus materially shortened and the expenditure of current in heating the dies is reduced.

A metallic ring 30 is carried by the hub 12 but suitable insulating material.

is insulated therefrom by a ring 31 formed of A plug 35 is connected to and carried by the outer face 20 of each die and extends through the back plate 15, a head 36 being formed on the plug and seating against the outer surface of the plate 15. An insulating bushing 37 surrounds the portion of the .plug extending through the back plate and the head 36 is insulated from the plate by an insulating washer 38.

The inner end of the plug 35 has secured thereto in any suitable manner, as by a nut 40, an electrical connecting conduit 41 which is also connected to the ring 30.

It will be understood that a separate conduit 41 is provided for each of the dies, all of these conduits being connected to the common ring 30. A spring contact member or wiper 45 engages the ring 30 and establishes an electrical connection therewith from a suitable source of electrical energy.

From the showing in the drawing it will be seen that the peripheral portion 50 of each die face 20 is connected to the back plate 15, thus establishing an electrical connection therewith. Since the back plate is secured to or formed on one of the arms 13, the frame or hub 12 of the carrier may be grounded by a wiper contact arm 51 and wire 52.

The conduit 41 and plug 35 are formed of metal having a low electrical resistance and the heating circuit will pass from the wiper 45 through the ring 30 and. through the conduits 41 and plugs 45 to the die faces 20 and through these faces to the back plates 15, arms 13, hub 12, and back to the other side of the power circuit. Since the face 20 of each die is formed of metal having a high electrical resistance, the face will be heated by the current passing therethrough and will thus exert a drying effect on the pulp articles deposited thereon. If desired the dies can be heated throughout a part of their revolutions. The duration of heating can be varied by changing the length of the conducting member 30.

Particular attention is called to the fact that the die faces or outer faces 20 vary in thickness from the center to the periphery thereof. This variation is made to insure an even heating of the entire surface of the die and the thickness is so varied that the cross sectional area of any circle described around the center of the die will be substantially the same as the cross sectional area of any other circle so described.

It is contemplated that the carrier having the heated dies thereon will be made relatively large in diameter so that the articles will remain on the heated dies a sumcient length of time to have the major portion ofmoisture thereon removed.

Although one specific embodiment of the invention has been particularly shown and described, it will be understood that the invention is capable of modification and that changes in the construction and in the. arrangement of the various cooperatmgparts may be made without departing from the spirit or scope of the invention, 'as expressed in the following claims.

What I claim is:

1. A die for pulp molding machines having a perforated face adapted to receive a layer of pulp thereon, a suction chamber communicating with said perforated face and means for heating the perforated face of said die to dry the layer of pulp thereon.

2. A die for pulp molding'machines adapted to receive a layer of pulp thereon, and electric heating means for said die comprising a circuit including the surface of the die on which the pulp is deposited.

3. In combination, a movable carrier, a suction die mounted thereon and adapted to receive a deposit of pulp, and means operable during the movement of the carrier and die for heating the die and thereby drying the pulp deposit.

4. In combination, a rotatable carrier, a suction die mounted thereon and adapted to receive a deposit of pulp, and means operable during the rotation of the carrier and'die for heating the die and thereby drying the pulp deposit.

5. A die for pulp molding machines adapted to receive a layer of pulp thereon, said die having a pulp receiving surface of relatively high electrical resistance and an electric heating circuit including said surface.

6. A die for pulp molding machines rotatable in a circular path, said die having a perforated face of high electrical resistance and a heating circuit for said die including said die face, and

rotatable contact members adapted to maintain a closed circuit during the rotation of the die.

7. A rotatable carrier having a hub, a plurality of dies mounted on said carrier, a metallic ring carried by but electrically insulated from said hub, said dies having faces adapted to receive a deposit of pulp and said faces being formed of metal having a relatively high electrical resistance, electric connections between said ring and said faces, and electrical heating circuits including the ring, electric connections and die faces.

8. A die for pulp molding machines having a face portion adapted to receive a deposit of pulp and formed of metal" having a high electrical resistance, a backing formed of heat insulating material disposed in the rear of said face portion, and an electric heating circuit electrically connected to said face portion.

9. A die for pulp molding machines having a face portion adapted to receive a deposit of pulp and formed of metal having a high electrical resistance, said face portion being varied in thickness from the center to the periphery thereof to insure a uniform heating thereof,

a heating die by suction, in heating the article by the die while drawing the moisture of the heated article towards its die contacting surface by the suction thereon.

12. In combination, a movable carrier, a die adapted to receive a deposit of pulp, means operable during the movement of the carrier and die for heating the die and pulp thereon and simultaneously operating means for drawing the moisture from the article.

13. In combination, a movable carrier, a die adapted to receive a deposit of pulp, means operable during the movement of the carrier and die for heating the die and pulp thereon, and means for simultaneously holding the pulp on the die .and exhausting the moisture.

14. In combination, a movable carrier, a die comprising a suction head mounted thereon and adapted to receive a deposit of pulp, means operable during the movement of the carrier and die for heating the die and pulp thereon while under the suction of the suction head to draw the moisture towards the heated die surface.

15. A die for pulp molding machines, said die having a perforated face adapted to receive a layer of wet pulp thereon, means for heating said die and means to exhaust the moisture from the heated layer of pulp thereon through the perforations of said face.

16. A die for pulp'molding machines adapted to receive a layer of wet pulp thereon, means for heating the face of said die and means to draw the moisture from the layer of pulp thereon towards the face of the die.

17. In combination, a movable carrier, a die mounted thereon and adapted to receive a deposit of wet pulp, and means simultaneously operable during the' movement of the carrier and die for heating the die and drawing the-moisture from the heated pulp deposit thereon.

18. In combination, a rotatable carrier, a die mounted thereon and adapted to receive a deposit of wet pulp, and means continuously operable during the rotation of the carrier and die for simultaneously heating the die and drawing the moisture from the heated pulp deposit thereon.

19. That improvement in the art of drying die molded pulp articles which consists in providing a die with a heating surface over which the article isadapted to be placed, and in applying vacuum to the opposite side of the die whereby progressively to draw the heat and the moisture given off by the heated article through the article in tempering relation thereto.

20. In combination, a die having a perforated face and adapted to dry a wet molded pulp article thereon, means for heating the die and thereby drying the article thereon, and means for drawing the moisture from the article through the perforations of said face.

21. In combination, a die adapted to receive a layer of wet pulp thereon, means for heating the die and thereby drying the layer of pulp thereon, and means for drawing the moisture from the heated layer of pulp while simultaneously holding the heated layer of pulp on the die.

22. In combination, a die adapted to receive a layer of wet pulp thereon, means for heating the die and thereby drying the layer of pulp thereon, and means operating simultaneously with the die heating means for holding the layer of pulp on the die while drawing the moisture therefrom.

23. In combination, a die having a perforated face adapted to receive a layer of wet pulp thereon, means for heating the die and thereby drying the layer of pulp thereon, and means operating simultaneously with the die heating means for drawing the moisture from the heated layer of pulp, through the perforations of said face; a

24. In combination, a suction die adapted to receive a deposit of pulp, means forapplying suc- 

